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Reflections in Nature: The annual fall migration is here

The annual fall migration is in full swing. Along with it comes one of the many fallacies concerning wildlife, that of hummingbirds riding on the backs of Canada geese when migrating south. This story stems from a magazine, with nationwide circulation, that had a tongue-in-cheek article about hummingbirds hitching rides on the backs of Canada geese.

I saw several flocks of migrating geese heading south. My diary tells me that the chimney swifts left our area in the middle of August. Most of our turkey buzzards have left the area, but there are a few stragglers.

Our word migration comes from the Latin word migrare, which means to wander. The words emigrate and immigration also come from migrare.

A few more words are mutate, meaning to change; commute, which means to exchange and commuter, one who makes daily trips between cities and suburbs.

Plato wrote, “Either death is a state of nothingness and utter unconsciousness or, as men say, there is a change and migration of the soul from this world to another.”

Although we know a great deal about the migration of our birds and animals, we still have a lot to learn about this movement of wildlife.

Aristotle, who lived in 384 B.C. to 322 B.C. wrote, “Some creatures stay put for the winter while others move south after the autumn equinox. These species move north again after the spring equinox, this time to avoid the heat.” He also made this observation,” All creatures are fatter in migration.”

Just how astonishing are some of these migrations?

Every year, as the summer wanes, willow warblers weighing only a few grams will undertake a journey of 5,000 miles to escape the harsh winter weather. In comparison to man’s weight, this is equivalent to traveling ten times the distance from the earth to the moon or 24,140,000 miles.

All eels from Europe and North America migrate to the Sargasso Sea, where they mate, give birth and die. The young will start and complete the journey back to their parent’s home without any aid from older and more experienced eels. For some of the young, this migration can take several years. If this is not amazing enough, a European eel has never been found in North America, and a North American eel has never been found in Europe.

The arctic tern performs a migration twice yearly that takes it from one pole to the other. This is a round trip of 25,000 miles that is unequalled by any other migrant. To complete this journey, the arctic tern must fly non-stop for eight months of the year. While on this migration, it will feed by plunging into the water to capture fish.

Atlantic salmon will spend most of their adult life, which can be one to four years, in the ocean and then begin the migration back to their birthplace to spawn and die. Salmon that return after only one year are called grilse.

They re-enter the freshwater rivers some twelve months before spawning. The longer the river the earlier the salmon must enter to arrive at the spawning grounds in time to breed. During the migration upstream, the salmon, which are an average of 28 inches long, travel six to twelve miles a day without feeding. A salmon can lose as much as 25% of its weight on the journey.

After spawning, a very high percentage of both males and females die. Only 26% survive to return downstream to the sea. The adult salmon that do make it back to the sea are known as kelt. They will spend four to eighteen months feeding in the sea before returning to freshwater. Of all spawning salmon, it is estimated that only three to six percent have spawned before.

The Pacific salmon that spawn in rivers bordering the Pacific Ocean have a similar life-history. However, they differ in that they all die after spawning.

The most famous insect migrator is the monarch butterfly. Its life cycle is closely related to the milkweed plant. The monarch’s migration is so predictable, with respect to direction and time of year, that towns along the monarch’s flight path celebrate their arrival with festivals. Pacific Grove, California, calls itself the “Butterfly City” because most of the monarchs west of the Mississippi River spend winters there.

The Bible refers to migration in Job 39:26 “Doth the hawk fly by thy wisdom and stretch her wings toward the south?” Birds of prey do regularly fly south in Autumn, especially in the middle eastern lands. Then, in Jeremiah 8:7 “Yea, the stork in the heaven knowth her appointed times; and the turtle dove and the crane and the swallow observe the time of their coming; but my people know not the judgement of the lord.”

Well, the migration is underway. It’s a long and dangerous journey to be sure, one which early man himself had participated in. Whether we understand it or not, wildlife will leave each fall and return each spring, guided by instinct, celestial bodies and perhaps things unknown.

Bill Bower is a retired Pennsylvania Game Commission Wildlife Officer. Read his blog and listen to his podcasts on the outdoors at www.onemaningreen.com.

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